CA1311265C - Seal structure for an electrochemical cell - Google Patents

Seal structure for an electrochemical cell

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Publication number
CA1311265C
CA1311265C CA000607183A CA607183A CA1311265C CA 1311265 C CA1311265 C CA 1311265C CA 000607183 A CA000607183 A CA 000607183A CA 607183 A CA607183 A CA 607183A CA 1311265 C CA1311265 C CA 1311265C
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Prior art keywords
particles
binder
layer
plates
electrochemical cell
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CA000607183A
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French (fr)
Inventor
Ronald G. Martin
Richard D. Breault
Warren L. Luoma
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UTC Power Corp
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International Fuel Cells Corp
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    • C04B37/00Joining burned ceramic articles with other burned ceramic articles or other articles by heating
    • C04B37/008Joining burned ceramic articles with other burned ceramic articles or other articles by heating by means of an interlayer consisting of an organic adhesive, e.g. phenol resin or pitch
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    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632Organic additives
    • C04B35/634Polymers
    • C04B35/63404Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63436Halogen-containing polymers, e.g. PVC
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/86Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/96Carbon-based electrodes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/02Details
    • H01M8/0202Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/02Details
    • H01M8/0202Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0267Collectors; Separators, e.g. bipolar separators; Interconnectors having heating or cooling means, e.g. heaters or coolant flow channels
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/02Details
    • H01M8/0271Sealing or supporting means around electrodes, matrices or membranes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/02Details
    • H01M8/0297Arrangements for joining electrodes, reservoir layers, heat exchange units or bipolar separators to each other
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
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    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/24Grouping of fuel cells, e.g. stacking of fuel cells
    • H01M8/241Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/24Grouping of fuel cells, e.g. stacking of fuel cells
    • H01M8/241Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
    • H01M8/2418Grouping by arranging unit cells in a plane
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/24Grouping of fuel cells, e.g. stacking of fuel cells
    • H01M8/2465Details of groupings of fuel cells
    • H01M8/2483Details of groupings of fuel cells characterised by internal manifolds
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    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30Constituents and secondary phases not being of a fibrous nature
    • C04B2235/48Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
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    • C04B2235/50Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
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    • C04B2235/5216Inorganic
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    • C04B2237/56Using constraining layers before or during sintering
    • C04B2237/568Using constraining layers before or during sintering made of non-oxide ceramics
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
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    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49002Electrical device making
    • Y10T29/49108Electric battery cell making
    • Y10T29/49115Electric battery cell making including coating or impregnating

Abstract

Abstract Seal Structure for an Electrochemical Cell A seal structure 58 between adjacent porous plates 18,20 and a method of making the seal structure for an electrochemical cell are disclosed. Various construction details are developed which facilitate fabrication and assembly. In one embodiment, the adjacent porous plates are electrolyte reservoir plates joined together at a three-layer seal structure to form an integral assembly.

Description

Description Seal Structure for an Electrochemical Cell Technical Field This invention relates to a seal for a porous plate of the type used in electrochemical cells, such as fuel cells for fuel cell powerplants. Although this invention was developed for use in the field of phosphoric acid fuel cell powerplants/ the invention has application to other electrochemical cells employing such seals including ~uel cells employing a base, or a solid polymer for an electrolyte.

Background of Invention Fuel cell powerplants produce electric power by electrochemically consuming a fuel and an oxidant in one or more electrochemical cells. The oxidant may be pure oxygen or a mixture of gase~ containing oxygen, such as air. The fuel may be hydrogen.
Each fuel c~ll generally has electrodes for ~-reacting the gases, such as an anode alectrode for fuel and a cathode electrode for an oxidant. The cathode electrode is spaced ~rom the anode electrode. A matrix saturated with electrolyte is disposed between the electrodes.
Each electrode includes a substrate. The 2S subRtrate has a catalyst layer disposed on the side of the substrate which faces the electrolyte matrix. In some instances an electrolyte reservoir layer, such as an electrolyte reservoir plate, is on the other side OL
the substrate and is capable o~ providing electrolyte through small pore~ in the reservoir plate to the substrate. These electrolyte reservoir plates may have channels or passageways behind the substrate for 131 12~5 carrying reactant ga es, such as channels for carrying gaseous fuel to the anode and channels for carrying gaseous oxidant to the cathode. For example, these channels might extend between parallel ri.bs on the substrate side of the electrolyte re~ervoir plate.
A separator plate on the other side of the electrolyte reservoir plate provide~ a balrrier to the trans~er of electrolyte and prevents mixing of the fuel and oxidant gases in adjacent cells.
Another acceptable construction is to have the electrode substrate act both as an electrolyte reservoir plate and as an electrode substrate with channels on the separator side of the substrate.
U.S. Patent 4,564, 427 issued to Gruver entitled "Circulating Electrolyte Electrochemical Cell Having Gas Depolarized Cathode with Hydrophobic Barrier Layer"
has a cathode which includes a porous plate for a substrate. A barrier layer o~ a fluorocarbon polymer containing carbon particles is bonded to the porous substrate plate and a catalyst layer is applied to the barrier layer. The barrier layer blocks the flow of electrolyte from passing through the catalyst layer to the substrate while permitting the flow of a reactant gas from the substrate through the barrier layer to the catalyst layer.
Other examples of electrolyte reservoir layers are shown in commonly owned U.S. Patents 3,779,811;
3,905,832; 4,~35,551: 4,~38,463; 4,06~,207; 4,08~,413;
4,064,322; 4,185,145; and 4,374,906.
Several of these patents show the electrolyte re~ervoir layer as an electrode substrate. In addition to accommodating changes in acid volume due to electrolyte evaporation and changes in operating conditions of the cell, electrode substrates must sati~fy several other functional requirements. For example, the substrate ~u~t be a good electrical conductor, a good thermal conductor and have adequ~te structural strength and corro~ion resistance. The substrate must provide support to the catalyst layer and provides a means for the gaeeous reactants to pas~
to the cataly~t layer. Finally, the edges of the ~uhstrate axe often required to function as a wet seal to prevent the escape of reactant gaces and electrolyts from the cell.
One way to form a wet seal i~ to recluce the pore size of the ~dge region by densifying the edge region, such as through compression during substrate fabrication, and providing a liquid, such a~
electrolyte to the densified edge region. Densified subs~rate edge seals are described in commonly owned U.S. Patents 4,269,642 and 4 365,008. Experience has shown that the seal density and pore size that can be practically obtained limits the edge seal cross pressure (or, commonly called the bubble pressure) to 3-4 psi.
Another approach to forming the seals is described in U.S. Patent 3,867,206 entitled i~WPt Seal for Liquid Electrolyte Fuel Cells" issued to Trocciola et alr which is commonly owned with the present invention.
Another example is shown in commonly owned U.S. Patent 4,259,389 issued to Vine en~itled "High Pressure-Low Porosity Wet Seal". As discussed in Vine, a seal may be formed in the ~dge seal region of a porous plate by using a powder filler to provide a denser packing to the region which reduces porosity.
An improved edge ~eal is described in copending, commonly owned, U.S. Patent 4,652,502 entitled "Porous Plate for an Electrochemical Cell ~nd ~ethod for Making : -3-the ~orous Plate'~ filed by Richard D. Breault, a coinventor of this application, and John D. DonahueO
In this construction, the electrolyt~ res~rvoir layer is a substrate or an eleçtrolyte reservoir plate. The edge seal regions of such porous plates are filled with a high solids, low structure powder which is intr~duced into the region in suspension form under pressure. The pores of the seal are formed within the edge of the porous plate upon removal of the liquid :Erom the suspension. Such a seal is able to tolarate transient cross-pressures which are an order of magnitude larger than the cross-pres~ures encountered in the edge region during the normal operation.
Generally, a stack of fuel cells and separator plates are used in performing the electrochemical reaction. As a result o~ the electrochemical reaction, the fuel cell stack produces electric power, a reactant product, and waste heat. The stack includes a cooling system for removing the waste heat from the fuel cell stack. ~he cooling system has a coolant and conduits for the coolant dispo~ed in cooler holders to form coolers within the stack. Heat is tran6ferred by the cooler holders from the fuel cells to the conduits and from the conduits to the coolant.
The cooler holder must be electrically and thermally conductive and may be permeable to gas~ An exa~ple of such a cooler holder is shown in U.S. Patent 4,245,009 issued to Guthrie entitled ~Porous Coolant Tube Holder for Fuel Cell Stack'~. Alternatively, the cooler holder might be impermeable to gas. An example of such a cooler holder is shown in U.S. Patent 3,990,913 issued to Tuschner entitled "Phosphoric Acid Heat Transfer Material". In Tuschner/ the cooler holder serves the double function of cooler holder and separator plate.
As discussed, separator plates prevent the mixing of the fuel gas, such as h~drogen, disposed s on one side of the sepaxator plate, with an oxidant, such as air, disposed on the other side of the separator plate. Separator plates must be highly impermeable to gases such as hydrogen and oxygen, and thermally and electrically conductive to pass heat and electrical current through the fuel cell stack. In addition, separator plates must also tolerate the severe corrosive atmosphere formed by the electrolyte of the fuel cell, such as hot phosphoric acid, while preventing electrolyte transfer from cell to cell. Finally, separator plates, like cooler holders, must be strong, particularly in terms of flexural strength, which is a measure of the ability of the separator plate to withstand high pressure loads, differential thermal expansion of mating components, and numerous thermal cycles without cracking or breaking.
An example of a method for making separator plates for electrochemical cells is dis-cussed in U.S. Patent 4,360,485 issued to ~manuelson 2s et al. In this method, the separator plate is formed by molding and then graphitizing a mixture of preferably 50 percent high purity graphite powder and 50 percent carbonizable thermosetting phenolic resin. In particular, Emanuelson discusses forming a well blended mixture of the appropriate resin and graphite powder. The mixture is then distributed in a mold. The mold is compacted under pressure and temperature to melt and partially cure the resin and to form the plate. Typically, such a plate must be 3s heated to for examplej to one-thousand 5 ~

degrees (1000C~ Celsius to convert the phenolic resin to carbon and then graphitized by heating to two~thousand seven hundred (2700~C) Celsius to provide required corrosion resistance.
The separator platel because it is a separate component, adds complexity and expen~e to the manufacture of a fuel cell stackO Efforts have been directed at eliminating such components by providing a seal structure within the porous plates. O~e example o such a seal structure is shown in U.S. Patent 4,756,981 issued to Breault et al. entitled "Seal Structure for an Electrochemical Cell". Breault discloses a seal region for adjacent porous plates which performs the function of a separator plate with a hydrophobic liquid barrier and a hydrophillic gas barrier.
Other efforts have been directed at eliminating such components by bonding together adjacent plates.
For exampl~, a gas separator disposed between the adjacent cathode and anode porous members might be a gas impermeabl~ layer as discussed in U.S. Patent 4,129,685 issued to Damiano ~ntitled "Fuel Cell Structure". In Damiano, two porous members may provide a flow path for the flow of a reactant gas and may be bonded to each other by the gas separator layer that i5 a thick or thin coating.
U.S. Patent 4,505,992 i~sued to Dettlin~ et al.
entitled an "Integral Gas Seal ~or Fuel Gas Distribution As~emblies and Method of Fabrication'~ is another example of such constructions. The gas distribution plate ~embers are bonded together at their interface with a sealant material which extends into the pores of at least one of said porous plates. The sealant material ~ay be selected from the group 1 3~ 1 265 consistin~ of fluorinated ethylenerpropylene, polysulphone, polyethersulfone, polyphenylsulphone, perflorinated alkoxy tetrafluoroethylene, and mixtures thereof.
Dettling describes a fabrication process for ~orming the integral assembly of the two porous plates.
The process includes providing two porous plates and a layer of sealant material between the plates. The plates and layer of sealant material are subjected to pressure and elevated temperature to melt the layer.
As a result, the ~aterial in the layer impregnates the porous plates as it melts flowing into the pores to bond the plates togethar and to seal each plate along the interface against gas transfer.
As noted in Dettling, the pressure applied to the two carbon plates must be great enough to force the facing surfaces o~ the plates together but not so great as to damage the underlying structure of the plates.
The above art notwithstanding, scientists and engineers are still seeking to develop seal structures for use between the porous plates of electrochemical cells such as the integral separator plates or other plates in abutting contact.

Disclosure of Invention According to the present invention, an electrochemical cell assembly includes a pair of gas porous plates joined together by a layer o~ binder and compacted particles disposed between the plates, such that the binder extends into the plates to form a bond, the boundaries of the layer and the porous plates are merged, and khe layer pas~ee heat and electrical charge while blocking the passage of liquid and gases between the plates.

In accordancs with one embodiment of the present invention, the electrically and the~mally conductive particles are carbon and the density of carbon particles in binder of the layer between the plates is greater than the density o~ carbon particles in binder of each of the layers in the adjacent porous plates.
According to the present invention, a method o~
foxming an electrochemical cell assembly includes:
disposing a binder and particle~ between adjacent porous plates; heating and pressing the porous plates against the binder and carbon particles to cause the binder to flow into the porous plates and to compact carbon particles in the layer between the porous plates; and, cooling the ~lowable binder under pressure to ~orm an integral assembly.
A primary ~eature of the present invention is a pair of gas porous plate~ ~ormed oE electrically and thermally conductive particles. A layer of binder and particles extends between the plates. The binder extends into each of the plates to form adjacent layers of particles in binder. Another feature is the relative po ition of the boundarie~ of the layers of particles in binder r In one embodi~ent, each boundary of the layer between the platss is merged with the boundary of the layer in the adjacent plate. In one parti~ular embodiment, the particles are graphite and the intermediate layer has a concentration of particles in binder which is greater than the density o~
particles in binder in the layers of the adjacent plates~
The principal advantage of the present invention is the gas impermeability o~ a seal ~tructure which r~sult~ from th~ compacted, particle filled, layer o~
binder (third layer) and the merged boundaries between 131 1~65 the third layer and the filled layers in theadjacent porous plates. Still another advantage is the reduced cost and complexity of the fuel cell in manufacture and use which results from forming s adjacent porous plates as an integral assembly by bonding together two electrolyte reservoir plates with a layer. In one particular embodiment, adja-cent electrolyte reservoir plates are joined and sealed without the use of a separate plate and are 10 formed as a one-piece assembly. An advantage of the method making the assembly is the filtering effect which is provided by the adjacent porous plates, forcing the carbon particles disposed throughout the intermediate layer into a compacted layer while providing a binder between the third layer and the adjacent porous plates. Another advantage is the immobilized bonded structure which results from the step of cooling the plates while applying pressure so that the plates and binder are cooled to a tempera-ture which insures that separation does not occur. Finally, other advantages of the method are the many different approaches which are available for disposing the third layer between the porous plates which enables adaptation of the manufacturing 2s process to a variety of high speed operations. An example is the method of forming a continuous sheet of graphite disposed in binder through molding a billet and skiving the continuous sheet from the billet.
From a broad aspect, and in accordance with a particular embodiment of the invention, there is provided an electrochemical cell assembl~ which includes a pair of adjacent gas porous plates having electrically and thermally conductive particles 35 joined together leaving a void structure therebetween, the plates being joined together to ; _ 9 _ , . .

1 31 ~ 265 form an integral structure that is electrically and thermally conductive and which includes a region that blocks the flow of gas and electrolyte, wherein the improvement comprises:
a first porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the first plate having a first surface which has a boundary defined by the particles;
a second porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the second plate having a second surface which has a boundary defined by the particles, the second S surface being spaced from the first surface leaving a region therebetween; and binder which is disposed in the region between the plates, the binder extending through the boundary of the first plate into the void structure to form a first layer of particles in binder in the first plate, and extending through the boundary of the second plate into the void structure to form a second layer of particles in binder in the second plate;
2s wherein electrically and thermally conductive particles are disposed in the region between the plates in the binder to form a third layer of particles in binder, the third layer having a first surface adjacent to the first surface of the first porous plate and a boundary defined by the particles of the third layer which is merg~d with the boundary of the first porous plate, the third layer having a second surface adjacent to the second surface of the porous plate ana a boundary defined ~s by the particles of the third layer which is merged with the boundary of the second porous plate.

: - 9a -.

.

From a different aspect, and in accordance with a particular embodiment of the invention, there is provided a method for making an electrochemical cell assembly which includes a pair of adjacent gas s porous plates having elec-trically and thermally conductive particles joined together leaving a void structure therebetween, the plates being joined together to form an integral structure that is electrically and thermally conductive and which includes a region that blocks the flow of reactant gas and electrolyte, which includes the steps of:
~ orming a first porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the first plate having a first surface which has a boundary defined by the particles;
forming a second porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the second plate having a second surface which has a boundary defined by the particles, the second surface being spaced from the first surface leaving a region therebetween;
disposing an intermediate layer between zs the plates such that the layer contacts the first surface of each plate, the intermediate layer consisting essentially of a binder and electrically and thermally conductive particles distributed throughout the binder, the intermediate layer having an initial concentration of particles in binder;
integrally joining the intermediate layer and the po~ous plates at a temperature and a pressure which forces the binder through the boundaries of the adjacent plates into the void structure and around particles in the adjacent plates to form a first layer of particles in binder - 9b ~

in the first plate, to form a second layer of particles in binder in the second plate, and to form from the particles disposed in the intermediate hinder ].ayer a third layer of particles in binder s disposed between the plates, the third layer having a first surface adjacent to the first surface of the first porous plate and a second surface adjacent to the second surface of the second porous plate;
cooling the plates and the third layer to 10 a temperature which prevents separation of the porous plates and the intermediate layer while applying pressure to the assembly;
wherein the concentration of particles in binder in the third layer after cooling is at least twice the initial concentration of particles in binder in the intermediate layer which exists prior to the step of integrally joining the intermediate layer and the porous plates.
The foregoing features and advantages of the present invention will become more apparent in light of the following detailed description of the best mode for carrying out the invention and the accompanying drawings.

g ~

131 12~5 Brief Description of the Drawings Figure 1 is a cross sectional view of a portion of an electrochemical cell stack having a pair of gas porous plates joined together by a layer o~ binder that contains compacted particles.
Figure 2 is a photomicrograph at one hundred times magnification of the layer of binder and compacted particles.
Figure 3 is a schematic representation of porous plates similar to the porous plates shown in Fig. 2 showing the relative orientation of the particles in the plate to the sectioned portion of each particle as it might appear in a photomicrograph.
Fig. 4 is a schematic representation of the two porous plates of Fig. 3 ~howing the relationship of the assembled plates to the particles disposed in the binder.

Best Mode for Carrying Out the Invention Figure l is a cross-sectional view o~ an embodiment of the pr~sent invention which is employed in an electxochemical cell assembly such as a fuel cell powerplant. A portion of a fuel cell stack 2 of such a p~werplant is shown.
The fuel cell stack 2 includes one or more fuel cells as represented by the fuel cell 4 and a portion of the adjacent cell 4a. Each fuel cell is box-like having two planar faces, such as the planar surface 6;
and, having sides or edges, such as four edges represented by the singls edge 8~ Cooler holders, represen~ed by the single cooler holder 10, are spaced at intervals between sets of fuel cells~ The cooler holders are adapted to recei~e conduits 11 for a coolant.
--10~

Each fuel cell includes an electrolyte retaining matrix 12 disposed between an anode elec~rode 14 and a cathode electrode 16. An electrolyte reservoir plate 18 is adjacent the anode and an electrolyte reservoir plate 20 is adjacent the cathode. The term '~plate" is used in its broad sense and includes plates that are curved or flat and porous or solid. The particular electrochemical cell shown uses phosphoric acid a~ the electrolyte.
Each anode electrode 14 has a catalyst layer 22 and an electrode substrate 24 which supports the catalyst layer. The substrate is a porous plate and acts as a gas permeable reservoir layer for the electrolyte. The catalyst layer is bonded to the substrate and is formed of catalyst particles bonded together with a hydrophobic material such as polytetrafluoroethylene. One such catalyst is platinum supported on carbon particles.
The porous electrolyte reservoir plate 18 has ribs 26 and an edge portion 28. The ribs are spaced apart leaving passages 29 for fuel therebetween which extend laterally across the plate in the Y-direction to one of the edges 8 (not shown) of the cell. A suitable fuel, such as hydrogen, is flowed through the passages 29 and the substrate reservoir layer 24 to the catalyst layer 22.
Electrolyte trans~er between the matrix 12 and both the electrolyte reservoir plate 18 and the reservoir layer 24 occurs directly through the pores of the catalyst layer 22 which is partially hydrophilic.
The catalyst layer ~ay have holee to aid in this liguid transfer. This distribution of electrolyte within the cell occurs as a result of the capillarity of porous structures (that is, the surface tension phenomenon of the gas-liquid interface) which causes the porous structure to develop capillary orces. The smaller the pore, the larger the capillary force and the greater the liquid retention capability.
The cathode electrode 16, like the ,anode electrode 1~, has a substrate 30 and a catalyst layer 32. The catalyst layer is bonded to the sub~trate.
The electrolyte reservoir plate 20 adjacent the cathode has a plurality of ribs, as represented by the single rib 34~ The ribs are spaced apart to de~ine passages 38 for the oxidant which extend laterally in the X-direction across the plate to the edge 8 (shown).
These passages generally extend perpendicular to the passages 29. An oxidant, such a~ the oxygen contained in air, is flowed through these passages 29 between the substrate reservoir layer 30 and the electrolyte reservoir plate 20 and from the passages 29 through the sub~trate to the catalyst layer 32.
Each porous plate having a reservoir layer is formed of relatively small fragments (particles) o~ a ~aterial or materials that are electrically and thermally conductive and are compatible with the environment. Such parti¢les include carbon, graphite, and boron carbide.
2S Because plates having reservoir layers are porous, each such plate has a peripheral seal region, such as the seal regions which block the loss of gases from passages 29. For example, the anode substrate 24 has a peripheral seal region 40, the cathode su~strate 30 has a periph0ral seal region 42, and the electrolyte reservoir plate~ 18 have peripheral seal regions in the edge region 28. In the edge region 28, the seal regisn extends parallel to the endmost passage o~ the passages 29. While the edge region o~ the cathode electrolyte 131 12~5 reservoir plate 20 is not shown, the seal region extends parallel to the endmost pa~sage of the passages 34.
Each seal region is filled with a sealing material to adapt the seal region to orm a seal with ~he electrolyte~ The sealing material comprises an inert powder selected from the group consisting of carbon, graphite, silicon carbide and ~ixture~ thereof. The powder has a particle size which is less than one micron and a low structure to facilitate dispersal of the powder to the original pri~e particles to aid in forming a high solid, low viscosity suspension. The sealing material increases the density of the seal region of the substrate thus decreasin~ the pore size and porosity o~ the plate.
Thus, substantially all the pores (that is, the pore size distribution) o~ the edge region are smaller than substantially all the pores (the pore size distribution) in a region spaced away from the edg~
region, such as the region in the ribs 26. Because the pores of the seal region are smaller than the remainder of the plate, the entire volume of the seal region remains essentially completely filled with electrolyte and no path for gas extends through the seal as lonq as the pore size of the edge region is smaller than the pore size of the matrix or, if larger, as long as the matrix 12 and edge region are filled with electrolyte.
Liquid seals are thereby formed by sandwiching the seali~g portion~ between the edge portions of the upper adjacent structure at 45 and the edge portion of the lower adjacent structure at 54. Thus, these liquid seals extend to the locations 45, 46, 48, 50, and 5~.
The capillarity resulting from the surface tension of liquid in porous structures, such as electrolyte in the seal region, causes capillary forces which resistmovement of the liquid electrolyte from the pores of the seal region. The smaller the pore, the larger the capillary forc~ at the gas-liquid interface and the larger the ability to resist dif~erences in pressure between any reactant gas and the exterior o~ the cell.
By reason of the method used to fill the seal formed in the substrate can resist steady state gas pressures and even transient differences in pressure which can range betw~en five and thirty pounds per square inch, absolute (5 and 30 psia).
A seal structure 5~ is provided to the cell 4 ancl the adjacent cooler holder at face 6 and extends laterally in the x-y directions. A laterally extending seal structure 58 is provided to the adjacent pair of cells 4, 4a. The seal structure extends through the faces 6a and 6b and is formed of three layers of particles and binder as discussed with respect to Fig.
2. The seal st-ructure extends laterally to the edges of the porous plates to prov~de means for blocking the passage of electrolyte and of reactant gases from fuel cell 4 and fuel cell 4a. Thus, the seal structure 58 blocks the leakage of gaseous reactants and electrolyte through the faces 6a and 6b in a direction 2 which is generally normal (perpendicular) to the lateral directions X and Yu Fig. 2 is a photomicrograph at a hundred times magnification of the seal structure 58 shown in Fig. 1.
This figure shows portions of the gas porou electrolyte reservoir plate 18 for the anode and the gas porous electrolyte reservoir plate 20 for the cathode.
The seal structure 5~ includes a layer of polymer bi~der which appears as black areas 60 in the photomicrograph, and potting compound which appears as gray areas 62. The potting compound is added to the porous plates for s~pporting th~ carbon particles of the plate during the polishing of the samples prior to making the photo~icrograph and is not part of the component. Carbon particles disposed in the plate and carbon particles disposed between the plates in the binder appear as irregularly shaped objects 64 lighter in color than the polymer binder 60 and .lighter in color than the potting compound 62.
The binder is disposed between the plates 18, 20 and ~xtends into the void structure of the adjacent porous plates~ The binder, a single continuous layer of material, forms three different layers with boundaries defined by the particles in each layer. The boundaries are merged at the interface between the layers. In particular, the binder extends into the adjacent porous plates 18, 20 and forms layers of carbon particle~ and binder in the plates such as the first layer 66 and the second layer 68. The binder between the plates forms the third layer 70 of carbon particles and binder.
Each layer has a distribution of carbon par~icles in binder. The amount of carbon particles present is measured in grams per cubic centimeter. This amount i~
referred to as the concentration of carbon particles in binder. In the porous plat~s, the concentration of carbon particles in binder .is in the order of one (1.0) gra~ per cubic centimeter o~ volume. The third layer between the porous plates has a concentration in the order of one and two tenths to one and four tenths ~1.2 to 1.4) gr~ms per cubic centimeter. Thus, the concentration of carbon particles in the third layer i5 greater than the conc~ntration of carbon particle~ in 1 31 1 2~5 the layers of the porous plates. As can be seen from the photomicrograph, within the third layer the concentration of carbon particles in binder is greater at the interfaces between the third layer and the adjacent layers in the porous plates than on the interior of the third layer.
In the acid electrolyte environment o~ the present embodiment, the carbon particles are graphitized a~d are pre~erably graphite for corrosion reæistance having a particle size which is equal to or greater than two microns, a low surface area (that is, less ten ~10~
square meter per ~ram, a low porosity), (that is, l~ss than or equal to twenty ~20) percent), and a high bulk density (that is, greater than seven-tenths (0.7) of a gram per cubic centimeter.
In the alkaline electrolyte environment of base fuel cells, such as potassium hydroxide cells, or in the environment of solid polymer electrolyte cells, other particles might be used which are of a material which is compatible with the electrolyte, such as nickel for a potassium hydroxide cell.
Fig. 3 is a schematic representation of portions of two porous electrolyte reeervoir plates similar to the plates shown in Fig~ 2 prior to fabrication of the assembly. Prior to fabrication, the plate~ are separated by a distance of about fourteen (14) mils leaving a space therebetween and a mixture of particles in binder is disposed in the space between the plates.
The binder and particles between the plates are not shown for the sake of clarity.
As shown in Fig. 3, each porous plate has electrically and thermally conductive parkicles, such as the carbon cathode particles 64a or the carbon anode particles 64b. The particles are joined together leaving a void structure therebetween. Because the particles are three dimensional object~ and the photomicrograph is a two-dimensional view of the particles, the particles shown in the photomicrograph are rPpresented with sectioned portions l:o show the portions of each particle in the plane oiE the photomicrograph and are represented with portions in full to show the portions of each particle which extend below the plane o~ the photomicrograph.
Each porous plate has a surfac~ and a boundary on the surface which is defined by the particles of the plate. For example, the cathode electrolyte reservoir plate is a first porous plate 20 having a first surface 74. The ~irst surface nas a boundary which is defined b~ the carbon particles 64a, as represented by the boundary line 76 extending in phantom. The anode electrolyte reservoir plate 18 is a second porous plate having a second surface 78 which faces the first porous plate. The second surface is spaced from the first surface leaving a region 80 therebetween. The second ~urface of the second porous plate has a boundary which : i~ de~ined by the particles 64b in the porous plate as represented by the phantom line 82.
Fig. 4 shows the relationship of the particles of the third layer 70 to the particle~ between the porous plates. After fabrication, the two plates will be adjacent to the third layer and spaced apart by a final distance t~ of approximately ~even (7) mils. Because - the binder extends into the adjacent plates, the immobilized particles in the adjacent plate displace the smaller particles and the binder causing the binder to extend into the plates a distance Ba and Bc such that the su~mation o~ the final thickness tf between the plates and the distance Ba and B~ is greator than the initial thickness ti. The binder is not shown for the sake of clarity. Because the method of ~abrication forces the smaller particles of the third layer together, the third layer has a concentration of particles at the boundary which extend a distance Ca and Cc, for example, of about two mils over the adjacent boundaries of the por~us plates on either side of the third layer. As noted, the particles i.n the third layer are in greater conc2ntration ~n these regions of the third layer than in the interior of the third layer.
More particularly, the third layer of binder is filled with carbon particles and has a first surface 84 adjacent to the first surface 74 of the first porous plate 20. The first surface 84 has a boundary 86 defined by the particles of the third layer. The boundary 86 is merged with the boundary 76 of the first porous plate.
The third layer has a second surface 88 adjacent to the second surface 78 of the ~econd porous plate 18 and a boundary 90 defined by the particles of the third layer. The boundary 90 is merged with the boundary 82 of the second poxous plate. The boundaries are considered merged because particles ~rom the third layer which define the boundary of the third lay~r extend over the particles from the adjasent layers which ~orm the boundaries for those layers. As a result, the boundaries of each layer extend past the boundaries o~ the adjacent layer.
The method of making the assembly includes the steps of forming the two porous plates, such as electrolyte reservoir plates, which are to be joined together. These steps are well Xnown and include ~orming graphite and phenolic resi~ precursor structures, carbonizing and graphitizing the structures to form the porous electrolyte reservoir plates, microgrinding the reservoir plates to uniform thickness, trimmin~ the plates and then s vulcanizing the plates. An example of such a process is shown in U.S. Patent 4,1~5,1~5 and U.S.
Patent 4,219,611 which are issued to Breault and are entitled "Fuel Cell ~lectrolyte Reservoir Layer and Method for Making".
A mixture of graphite powder and a resin is formed for disposition between the porous plates.
The mixture of graphite powder and the resin, such as Teflon resin or other suitable resins, is dry blended for about twenty minutes for a fifty pound batch using a Littleford ~ mixer - Model FM-130 or the equivalent. Satisfactory powders have been found to be Carbon/Graphite Group Inc. (CGGI) Grade 60 powder, si.eved through 1~ mesh screen to remove all particles above 105 microns. The mean particle size is approximately thirty-five microns. Another suitable graphite powder is CGGI Grade 90 powder.
Both of these powders are available from the Carbon/Graphite Group Inc., St. Marys, Pennsylvania 15857. Other graphite powders found satisfactory 2s are: Grade 9033 Desulco O graphite powder avail-able from the Superior Graphite Company, Chicago, Illinois; and Grade 200-42 graphite powder available from Joseph Dixon Crucible Co., Jersey City, New Jersey 07303. Teflon O powders may include fluorinated ethylene propylene (FEP Teflon) powder such as grade TL-120 available from the LNP
Corporation, Malvern, Pennsylvania. Another suit-able Teflon powder is perfluoroalkoxy resin (PFA
Teflon) powder available as Teflon-P powder grade 3s number 532-5010 from the E.I. Dupont DeNemours &
Co., Wilmington, Delaware 198~8.

.. .

After forming the graphite-Teflon powder mixture, the mixture is deposited on an ~lectrolyte reservoir plate, the mixture consisting essentially of graphite powder and the Teflon binder. Several methods of deposition are possible. The powder mixture may be deposited in the dry condition by (1) mechanical spreading using a doctor blade, (2) vacuum deposition of a fluidized powder, (3~ pa sing the part under a rotary brush ~eeder. The powder mixture ~ay also be made into a slurry by use of an appropriate vehicle and either ~lip cast, screen printed, or ~iltered onto the part, and then dried to remove the v hicle.
The total amount of material deposited is in the range of 0.2 to 0.6 grams per square inch. The powder mixture can be cold compacted by rolling to improve its green strength which facilitates handling.
An alternate method of disposing the graphite-Teflon powder mixture on the electrolyte reservoir plate is to use a manufacturing process which involves disposing a sheet of suitable material between the reservoir plates. The heet is obtaine~ by first forming a billet of suitable materials and then skiving sheets from the billet. The billet is formed by molding blended powders into a cylindrical shape. The steps of ~orming the billet are familiar to one skilled in the art and include blending the graphite and FEP or PFA Teflon powders, preforming the billet by compacting the powder under a pressure of at least one-thousand (lO00) pounds per square inch, sintering the preformed billet above the melt point of the resin under a pre~sure of at least one-thousand ~lO00) pounds per square inch to mold the billet to a density of greater than one and eight tenths ~1.8) grams per cubic centimeter. And, finally the densified billet is cooled under pressure to below the melt point of the resin. Thereafter, a continuous sh~et is skived from the billet to form a layer of material which is disposed between the electrolyte re~ervoir platesO
The two electrolyte reservoir plates and an intermediate layer of graphite powder and Teflon powder whether as a powder mixture or as a continuou~ sheet are placed together. The two plates and the intermediate layer are then laminated to ~orm a unitized electrolyte reservoir plate - integral separator plate assembly.
The process uses the following steps. First, the assembly of the two plate~ and graphite-resin powder is hea~ed to five hundred and eighty (580) to six hundred and fifty (650) degrees Fahrenheit at a pressure of two hundred (200) to three hundred (300) pounds per square inch for five to fifteen (5 to 15) minutes. This temperature and pressure forces the binder throuyh the boundaries of the adjacent porous plates into the void structure and around particles in the adjacent porous plates. As the binder moves into the plates, the binder forms layers of particles in binder in the adjacent plates as well as forming the third layer of binder and particles between the plates. As the porous plates move closer to each other due to pressure and the binder moving into the porous plates, the porous plates act as ~ilters pushing before the plates the fine particles that are in the intermediate layer.
This cau6es the fine particles in the intarmediate layer to compact with an increased concentration along the sur~ace of either side of the intermediate layer.
After the binder has moved into the porous plates and the layer between the p}ates has been compacted, the assembly is cooled to about ~ive hundred (500~ degrees 1 3 1 1 2~5 Fahrenheit or less while maintaining pressure.
Alternatively, the assembly is transferred quickly t9 a cold pres~ while above a temperature of five hundred and fifty (550) degrees Fahrenheit, the ~elting point of the FEP Teflon b.inder, and quenched ullder pressure.
In either event the binder is ~rozen in poaition while still under pressure.
A dual-belt press may be u ed to laminate th~
assemblies on a ~ontinuou~ basis. In this type of operation ~.ach side of the press has a belt which moves continuously with a laminate of electrolyte reservoir plat~ and layers therebetween. ~fter la~ination, the assembly is checked for gas permeability and for electrical resistance.
If the assembly is acceptable, edge seals are formed in the edge to prevent outboard gas leakage.
These may be ~ormed by impregnating the edge seal after lamination wlth fine particle graphite to create a wet seal. Alternatively, the edge seals may be introduced into the plate prior to lamination or by using solid seals which are bonded in place during the laminating process. Gas flow channels are then machined in the electrolyte reservoir plate/integral separator plate assembly. Finally the backside seal material is applied in the wet seal areas. The intermediate layer and adjacent layer of the assembly now exist as shown in FigO 4 and is ~imilar to the cross-sectional photo micrograph of the similar layers shown in Fig. 2.
Assemblies o~ two porous plates with three layers at the interface between the plates have been fabricated and characterized ~or gas leakage and eiectrical resistance be~ore and after heat aging.
Then the assemblies have b2en heat aged at ~our-hundred and forty (440) and ~500) five hundred degrees t ~ I ~ 2 l~i! 5 Fahrenheit with periodic the~mal cycling to xoom temperature. The result~ of the~e tests are shown in Tables 1 and 2 for various compositions which have been evaluated. These tables show the e~fect on important characteristics of the range in composition o~ the weight percentage of graphite, the types o~ graphite and the types of ~eflon that are used making the assembly. The results show that compositions with twenty-five (25) to forty (40) weight percent graphite powder with a mean graphite particle size o approximately thirty-five (35~ microns and a particle size that ranges between two to one-hundred and five (~-105) microns appear optimum in that both the low gas permeability in the dry condition (that is, less than .06 cc/ft2 sec) and an IR or voltage characteristic which is less than or equal to two and one-half millivolts per one hundred amps per square foot (100 ASF) across the ~onded layer are acceptable.
The gas permeability characteristic is measured by applying a cross pressure of eight (8) inches of water to the porous plates and measuring the permeability of the structure to gas as it passes through the dry structure. The gas that is used is nitrogen.
The IR or voltage characteristic is measured by compressing the porous plates between graphite plates to a pressure of 100 psi, passing a D.C. current of 100 ASF, and ~easuring the D.C. voltage drop across the porous plates.
As ~entioned earlier the minimum particle size is two microns and the small particles can be seen in the edge region adjacent to the layers in the porous plates. The concentration of small particles at the interface between layer~ and the merged boundary layers decrease the IR characteristic of the integral 1 31 ~ 265 assembly. This results from the use of a mixture ofgraphite and Teflon powder between the electrolyte r~servoir plates which has an excess o~ Te~lon powder in comparison to the ~inal composition of the third layer. The excess Teflon binder is forced from between the plates under pressure and driven into the pores of the adjacent porous plates during the high pressure, high temperature laminating process. This results in a co~pacted layer of carbon powder in ~raphite ~orm between the porous plates that contains the amount of Teflon material needed to ~ill the void volume but with no excess Teflon ~aterial to cause high electrical or thermal resistance. And, this method also results in merged boundaries between the layers with a high concentration o~ small particles at the boundaries further improving the electrical and thermal conductivity of the layers.
In one particular configuration, the porous plates were about twenty mils apart at the beginning of the asse~bly process. At completion of the fabrication process, the distance between the porous plates was approximately ten ~lO) mils. The mean particle size Pm was less than or equal to one-half of the distance t between the plates (Pm < t/2). This is important because mean particle sizes larger than that appear to adversely effect the ability of the three layers to block the leakage o~ gas or electrolyte through the layers although the plates may still be functional for some applications. Pre~erably, the mean particle size is approximately 20% o~ the distance t and the layer is approximatsly one-third by weight graphite particles.
As noted~ good results have been obtained using fluorinated ethylene propylene (FEP Teflon~ and ~4-perfluoroalkoxy (~FA Teflon) resin ~nd mixtures of these.
Although the invention has been hown and described with respect to detailed embod:iments thereof, it should be understood by those skilled in the art that various changes in orm and detail thereo~ may be made without departing ~rom the spirit and the scope of the claimed invsntion.

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Claims (30)

1. An electrochemical cell assembly which includes a pair of adjacent gas porous plates having electrically and thermally conductive particles joined together leaving a void structure therebetween, the plates being joined together to form an integral structure that is electrically and thermally conductive and which includes a region that blocks the flow of gas and electrolyte, wherein the improvement comprises:
a first porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the first plate having a first surface which has a boundary defined by the particles;
a second porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the second plate having a second surface which has a boundary defined by the particles, the second surface being spaced from the first surface leaving a region therebetween; and, binder which is disposed in the region between the plates, the binder extending through the boundary of the first plate into the void structure to form a first layer of particles in binder in the first plate, and extending through the boundary of the second plate into the void structure to form a second layer of particles in binder in the second plate;

wherein electrically and thermally conductive particles are disposed in the region between the plate in the binder to form a third layer of particles in binder, the third layer having a first surface adjacent to the first surface of the first porous plate and a boundary defined by the particles of the third layer which is merged with the boundary of the first porous plate, the third layer having a second surface adjacent to the second surface of the porous plate and a boundary defined by the particles of the third layer which is merged with the boundary of the second porous plate.
2. The electrochemical cell assembly of claim 1 wherein the first layer has a first concentration of particles in binder, the second layer has a second concentration of particles in binder and the third layer has a third concentration of particles in binder which is greater than the concentrations of the first and second layers.
3. The electrochemical cell assembly of claim 1 wherein said assembly is a fuel cell assembly, the pair of adjacent gas porous plates are a pair of electrolyte reservoir plates, wherein the particles are carbon, and wherein the integral assembly has a voltage characteristic which is less than or equal to two and one-half millivolts per one-hundred amps per square foot (2.5 mV/100 ASF) and an electrolyte permeability of zero and a gas permeability characteristic which is less than six-hundredths of a cubic centimeter of nitrogen (N2) per second per square foot (0.06 cc/sec-ft2) at eight inches of water pressure differential.
4. The electrochemical cell assembly of claim 2 wherein said assembly is a fuel cell assembly, the pair of adjacent gas porous plates are a pair of electrolyte reservoir plates, wherein the particles are carbon, and wherein the integral assembly has a voltage characteristic which is less than or equal to two and one-half millivolts per one-hundred amps per square foot (2.5 mV/100 ASF) an electrolyte permeability of zero, and a gas permeability characteristic which is less than six-hundredths of a cubic centimeter of nitrogen (N2) per second per square foot (0.06 cc/sec-ft2) at eight inches of water pressure differential.
5. The electrochemical cell assembly of claim 2 wherein the particles are graphite, the concentration of particles in binder in the third layer is in the range of one and two-tenths to one and four-tenths (1.2-1.4) grams per cubic centimeter and the concentration of particles in binder in the first and second layers is one (1.0) gram per cubic centimeter.
6. The electrochemical cell assembly of claim 1, 2, 3, 4, or 5 wherein the particles disposed in said third layer are carbon particles in the form of graphite, the third layer is sixty to seventy weight percent graphite particles having a mean particle size Pm of thirty-five microns and being passable through a mesh screen having a predetermined size.
7. The electrochemical cell assembly of claim 6 wherein the mesh screen is a one-hundred and forty sieve mesh screen.
8. The electrochemical cell assembly of claim 7 wherein the minimum particle size is two microns.
9. The electrochemical cell assembly of claim 8 wherein the distance between the porous plates is t and the mean particle size Pm is less than or equal to one-half of the distance t (Pm ? t/2).
10. The electrochemical cell a assembly of claim 9 wherein the mean particle size Pm is approximately twenty percent of the distance t and wherein the layer is approximately two-thirds by weight graphite particles.
11. The electrochemical cell assembly of claim 10, wherein the binder is selected from the group consisting of fluorinated ethylene-propylene (FEP
Teflon), perfluoroalkoxy (PFA Teflon) resin and mixtures thereof.
12. The electrochemical cell assembly of claim 1 wherein the binder is any suitable polymer which has an acceptable thermal stability and chemical compatibility including polyethylene, fluorinated ethylene-propylene resin, perfluoroalkoxy resin, and mixtures thereof.
13. The electrochemical cell assembly of claim 12 wherein the binder is selected from the group consisting of fluorinated ethylene-propylene, perfluoroalkoxy resin, and mixtures thereof.
14. The electrochemical cell assembly of claim 2 wherein the binder is selected from the group consisting of fluorinated ethylene-propylene, perfluoroalkoxy resin, and mixtures thereof.
15. The electrochemical cell assembly of claim 3 wherein the binder is selected from the group consisting of fluorinated ethylene-propylene, perfluoroalkoxy resin, and mixture thereof.
16. The electrochemical cell assembly of claim 4 wherein the binder is selected from the group consisting of fluorinated ethylene-propylene, perfluoroalkoxy resin, and mixtures thereof.
17. The electrochemical cell assembly of claim 5 wherein the binder is selected from the group consisting of fluorinated ethylene-propylene, perfluoroalkoxy resin, and mixtures thereof.
18. The electrochemical cell assembly of claim 6 wherein the binder is selected from the group consisting of fluorinated ethylene-propylene, perfluoroalkoxy resin, and mixtures thereof.
19. The electrochemical cell assembly of claim 6 wherein the binder penetrates a distance into each porous plate that which is equal to or greater than one-half of the thickness of the third layer.
20. A method for making an electrochemical cell assembly which includes a pair of adjacent gas porous plates having electrically and thermally conductive particles joined together leaving a void structure therebetween, the plates being joined together to form an integral structure that is electrically and thermally conductive and which includes a region that blocks the flow of reactant gas and electrolyte, which includes the steps of:
forming a first porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the first plate having a first surface which has a boundary defined by the particles;
forming a second porous plate having electrically and thermally conductive particles which are joined together leaving a void structure therebetween, the second plate having a second surface which has a boundary defined by the particles, the second surface being spaced from the first surface leaving a region therebetween;
disposing an intermediate layer between the plates such that the layer contacts the first surface of each plate, the intermediate layer consisting essentially of a binder and electrically and thermally conductive particles distributed throughout the binder, the intermediate layer having an initial concentration of particles in binder;

integrally joining the intermediate layer and the porous plates at a temperature and a pressure which forces the binder through the boundaries of the adjacent plates into the void structure and around particles in the adjacent plates to form a first layer of particles in binder in the first plate, to form a second layer of particles in binder in the second plate, and to form from the particles disposed in the intermediate binder layer a third layer of particles in binder disposed between the plates, the third layer having a first surface adjacent to the first surface of the first porous plate and a second surface adjacent to the second surface of the second porous plate;
cooling the plates and the third layer to a temperature which prevents separation of the porous plates and the intermediate layer while applying pressure to the assembly;
wherein the concentration of particles in binder in the third layer after cooling is at least twice the initial concentration of particles in binder in the intermediate layer which exists prior to the step of integrally joining the intermediate layer and the porous plates.
21. The method for making an electrochemical cell assembly of claim 20 wherein the third layer disposed between the plates has boundaries at the first surface and at the second surface of the third layer which are defined by particles in the third layer and wherein, after the step of cooling the plates and the third layer, the boundary of the first surface of the third layer is merged with the boundary of the first surface of the first porous plate and the boundary of the second surface of the third layer is merged with the boundary of the second porous plate.
22. The method of making an electrochemical cell assembly of claim 20 in which the first layer has a first concentration of particles in binder and the second layer has a second concentration of particles in binder after the step of cooling: wherein the step of disposing an intermediate layer of particles and binder between the two porous plates includes disposing an intermediate layer having an initial concentration of particles in binder which is smaller than said first concentration and said second concentration of particles in binder in the porous plates; wherein the step of integrally joining the porous plates and the intermediate layer causes the porous plates to force particles in the intermediate layer toward the center of the intermediate layer at the binder moves into the porous plates; and, wherein, after the step of cooling the integral plates and the third layer, the third layer has a third concentration of particles in binder which is greater than the concentrations of particles in the first and second layers.
23. The method for making an electrochemical cell assembly of claim 22 wherein the step of disposing an intermediate layer between the porous plates includes depositing a graphite-binder powder mixture on the surface of at least one of said porous plates.
24. The method for making an electrochemical cell assembly of claim 23 wherein the step of depositing a graphite-binder powder mixture between the plates includes the step of depositing a slurry which includes graphite-teflon powder and a vehicle and includes the step of removing the vehicle prior to the step of integrally joining the intermediate layer and porous plates.
25. The method for making a component for an electrochemical cell assembly of claim 23 wherein the powder mixture is cold compacted by rolling to improve the handling characteristics of the powder mixture.
26. The method for making an electrochemical cell assembly of claim 22 wherein the step of disposing an intermediate layer between the porous plates includes the step of forming a sheet of graphite and binder mixture and disposing the sheet between the porous plates.
27. The method for making an electrochemical cell assembly of claim 26 wherein the step of forming the continuous sheet includes the step of molding a billet from the blend of graphite and binder powders and skiving the sheet from the billet.
28. The method for making an electrochemical cell assembly of claim 20,21,22,23,24,25 or 26 wherein the intermediate layer consists essentially of graphite powder and fluorinated ethylene-propylene resin, perfluoroalkoxy resin and mixtures thereof.
29. The method for making an electrochemical cell assembly of claim 28 wherein the mixture is approximately two (2) parts by weight resin and one part by weight graphite powder and is deposited in a range of two-tenths to six-tenths (0.2 to 0.6) of a gram per square inch.
30. The method for making a component for an electrochemical cell assembly of claim 29 wherein the assembly is heated to five hundred eighty to six hundred fifty (580-650°) degrees Fahrenheit at a pressure of two hundred to three hundred (200-300) pounds per square inch and wherein the assembly is cooled to five-hundred degrees Fahrenheit (500°F) or less while under pressure providing such pressure is applied while the binder is still flowable.
CA000607183A 1988-09-19 1989-08-01 Seal structure for an electrochemical cell Expired - Lifetime CA1311265C (en)

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Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5300124A (en) * 1993-03-31 1994-04-05 International Fuel Cells Corporation Method for forming a laminated electrolyte reservoir plate
DE19515457C1 (en) * 1995-04-27 1996-07-25 Mtu Friedrichshafen Gmbh High temp. fuel cell
US6020083A (en) * 1998-10-30 2000-02-01 International Fuel Cells Llc Membrane electrode assembly for PEM fuel cell
US6159628A (en) * 1998-10-21 2000-12-12 International Fuel Cells Llc Use of thermoplastic films to create seals and bond PEM cell components
US6387557B1 (en) 1998-10-21 2002-05-14 Utc Fuel Cells, Llc Bonded fuel cell stack assemblies
US6399234B2 (en) 1998-12-23 2002-06-04 Utc Fuel Cells, Llc Fuel cell stack assembly with edge seal
US6372376B1 (en) * 1999-12-07 2002-04-16 General Motors Corporation Corrosion resistant PEM fuel cell
WO2002001660A1 (en) * 2000-06-29 2002-01-03 Osaka Gas Company Limited Conductive composition for solid polymer type fuel cell separator, solid polymer type fuel cell separator, solid polymer type fuel cell and solid polymer type fuel cell system using the separator
JP2004312921A (en) * 2003-04-09 2004-11-04 Totan Kako Kk Metal coated carbon brush
US8986860B2 (en) * 2008-04-22 2015-03-24 GM Global Technology Operations LLC Integrated baffles for a fuel cell stack
KR20130024635A (en) * 2011-08-31 2013-03-08 엘지이노텍 주식회사 Reaction container and vacuum heat treatment apparatus having the same
JP2014074296A (en) * 2012-10-04 2014-04-24 Eco Board:Kk Paper partition for shelter
WO2024013503A1 (en) * 2022-07-15 2024-01-18 Focal Point Positioning Limited Method and apparatus that uses a transmission from a single transmitter for receiver positioning

Family Cites Families (61)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3481737A (en) * 1966-06-29 1969-12-02 Leesona Corp Matrix construction for fuel cells
US3442712A (en) * 1966-07-13 1969-05-06 United Aircraft Corp Fuel cell with absorbent means for removing or supplying electrolyte
US3519486A (en) * 1966-10-06 1970-07-07 United Aircraft Corp Control of electrolyte in a fuel cell
DE1671494B1 (en) * 1966-11-24 1971-11-04 Varta Ag METHOD OF MANUFACTURING A DOUBLE-SIDED GAS DIFFUSION ELECTRODE
US3634569A (en) * 1969-01-08 1972-01-11 United Aircraft Corp Method of manufacture of dense graphite structures
US3755243A (en) * 1969-01-08 1973-08-28 United Aircraft Corp Dense graphite structures
US3635682A (en) * 1969-06-13 1972-01-18 United Aircraft Corp Fuel cell reactor-burner assembly
US3762957A (en) * 1970-06-08 1973-10-02 United Aircraft Corp Method of fabricating lightweight electrodes
US3716609A (en) * 1970-10-05 1973-02-13 United Aircraft Corp Process for preparing molded structure from polyphenylene sulfide resin and filler
US3779811A (en) * 1971-03-16 1973-12-18 United Aircraft Corp Matrix-type fuel cell
US3748179A (en) * 1971-03-16 1973-07-24 United Aircraft Corp Matrix type fuel cell with circulated electrolyte
US3867206A (en) * 1973-12-21 1975-02-18 United Aircraft Corp Wet seal for liquid electrolyte fuel cells
US3912538A (en) * 1974-01-15 1975-10-14 United Technologies Corp Novel composite fuel cell electrode
US3905832A (en) * 1974-01-15 1975-09-16 United Aircraft Corp Novel fuel cell structure
US4017663A (en) * 1974-02-15 1977-04-12 United Technologies Corporation Electrodes for electrochemical cells
US3972735A (en) * 1974-02-15 1976-08-03 United Technologies Corporation Method for making electrodes for electrochemical cells
US4017664A (en) * 1975-09-02 1977-04-12 United Technologies Corporation Silicon carbide electrolyte retaining matrix for fuel cells
US4043933A (en) * 1976-06-15 1977-08-23 United Technologies Corporation Method of fabricating a fuel cell electrode
US4038463A (en) * 1976-09-01 1977-07-26 United Technologies Corporation Electrode reservoir for a fuel cell
US4035551A (en) * 1976-09-01 1977-07-12 United Technologies Corporation Electrolyte reservoir for a fuel cell
US4064322A (en) * 1976-09-01 1977-12-20 United Technologies Corporation Electrolyte reservoir for a fuel cell
US4115627A (en) * 1977-08-15 1978-09-19 United Technologies Corporation Electrochemical cell comprising a ribbed electrode substrate
US4115528A (en) * 1977-08-15 1978-09-19 United Technologies Corporation Method for fabricating a carbon electrode substrate
US4157327A (en) * 1977-12-27 1979-06-05 United Technologies Corporation Thermally conductive caulk
US4185145A (en) * 1978-09-11 1980-01-22 United Technologies Corporation Fuel cell electrolyte reservoir layer and method for making
US4233181A (en) * 1979-05-30 1980-11-11 United Technologies Corporation Automated catalyst processing for cloud electrode fabrication for fuel cells
US4219611A (en) * 1979-07-30 1980-08-26 United Technologies Corporation Fuel cell electrolyte reservoir layer and method for making
US4269642A (en) * 1979-10-29 1981-05-26 United Technologies Corporation Method of forming densified edge seals for fuel cell components
US4233369A (en) * 1979-10-29 1980-11-11 United Technologies Corporation Fuel cell cooler assembly and edge seal means therefor
US4245009A (en) * 1979-10-29 1981-01-13 United Technologies Corporation Porous coolant tube holder for fuel cell stack
US4279970A (en) * 1980-02-20 1981-07-21 Electric Power Research Institute, Inc. Electrochemical cell including ribbed electrode substrates
US4360485A (en) * 1980-08-25 1982-11-23 United Technologies Corporation Method for making improved separator plates for electrochemical cells
US4301222A (en) * 1980-08-25 1981-11-17 United Technologies Corporation Separator plate for electrochemical cells
US4345008A (en) * 1980-12-24 1982-08-17 United Technologies Corporation Apparatus for reducing electrolyte loss from an electrochemical cell
US4414291A (en) * 1980-12-24 1983-11-08 United Technologies Corporation Method for reducing electrolyte loss from an electrochemical cell
US4374185A (en) * 1981-05-14 1983-02-15 United Technologies Corporation High temperature, high pressure chemical resistant seal material
US4365008A (en) * 1981-07-27 1982-12-21 United Technologies Corporation Densified edge seals for fuel cell components
US4426340A (en) * 1981-09-29 1984-01-17 United Technologies Corporation Process for fabricating ribbed electrode substrates and other articles
US4374906A (en) * 1981-09-29 1983-02-22 United Technologies Corporation Ribbed electrode substrates
US4456645A (en) * 1981-10-22 1984-06-26 Energy Research Corporation Method of making an integral carbonized cooler assembly
JPS58117649A (en) * 1981-12-29 1983-07-13 Kureha Chem Ind Co Ltd Manufacture of electrode substrate of fuel cell
JPS5937662A (en) * 1982-08-24 1984-03-01 Kureha Chem Ind Co Ltd Electrode substrate for monopolar type fuel cell with two-layer structure
JPS5946763A (en) * 1982-09-10 1984-03-16 Kureha Chem Ind Co Ltd Two-layered electrode base plate for monopolar fuel cell
US4450212A (en) * 1982-09-30 1984-05-22 Engelhard Corporation Edge seal for a porous gas distribution plate of a fuel cell
DE3380999D1 (en) * 1982-09-30 1990-01-25 Engelhard Corp INTEGRATED GAS GASKET FOR A FUEL CELL GAS DISTRIBUTION PLATE AND METHOD FOR THE PRODUCTION THEREOF.
CA1202064A (en) * 1982-09-30 1986-03-18 Peter L. Terry Film bonded fuel cell interface configuration
US4526843A (en) * 1982-09-30 1985-07-02 Engelhard Corporation Film bonded fuel cell interface configuration
JPS59141171A (en) * 1983-01-31 1984-08-13 Nitto Electric Ind Co Ltd Conductor sheet
JPS59141172A (en) * 1983-01-31 1984-08-13 Nitto Electric Ind Co Ltd Conductor sheet with gas interceptibility
US4505992A (en) * 1983-04-11 1985-03-19 Engelhard Corporation Integral gas seal for fuel cell gas distribution assemblies and method of fabrication
US4695518A (en) * 1983-07-21 1987-09-22 United Technologies Corporation Silicon carbide matrix for fuel cells
US4574112A (en) * 1983-12-23 1986-03-04 United Technologies Corporation Cooling system for electrochemical fuel cell
JPS60236461A (en) * 1984-04-04 1985-11-25 Kureha Chem Ind Co Ltd Electrode substrate for fuel cell and its manufacture
US4605602A (en) * 1984-08-27 1986-08-12 Engelhard Corporation Corrosion protected, multi-layer fuel cell interface
US4530886A (en) * 1984-12-06 1985-07-23 United Technologies Corporation Process for humidifying a gaseous fuel stream
US4564427A (en) * 1984-12-24 1986-01-14 United Technologies Corporation Circulating electrolyte electrochemical cell having gas depolarized cathode with hydrophobic barrier layer
US4818640A (en) * 1985-09-25 1989-04-04 Kureha Kagaku Kogyo Kabushiki Kaisha Carbonaceous composite product produced by joining carbonaceous materials together by tetrafluoroethylene resin, and process for producing the same
US4652502A (en) * 1985-12-30 1987-03-24 International Fuel Cells, Inc. Porous plate for an electrochemical cell and method for making the porous plate
US4756981A (en) * 1986-12-29 1988-07-12 International Fuel Cells Seal structure for an electrochemical cell
JPH0677363A (en) * 1992-08-24 1994-03-18 Fujitsu Ltd Expandable radiation fin
JPH0677364A (en) * 1992-08-27 1994-03-18 Fujitsu Ltd Radiation fin

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JP3023117B2 (en) 2000-03-21
DK459189D0 (en) 1989-09-18
EP0360219A3 (en) 1991-05-15
US4913706A (en) 1990-04-03
EP0360219A2 (en) 1990-03-28
DK459189A (en) 1990-03-20
JPH02265169A (en) 1990-10-29

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